Late Dissection of Pulmonary Autograft Treated by Valve-Sparing Aortic Root Replacement

Abstract   Dissection of the pulmonary autograft is an extremely rare complication requiring emergent treatment as there is a chance of rupture and proximal aortic involvement. The autograft dissection can involve the aortic annulus, causing separation of leaflets from the annulus in addition to causing annular dilatation, thereby precluding resuspension of leaflets. The usual treatment in such cases is to perform the Bentall procedure, which involves placing a valved conduit (usually mechanical valve) and thereby necessitating anticoagulation. This report describes a case of successful valve-sparing aortic root replacement following the Ross procedure with dissection of autograft.     

Radioprotective effect of podophyllotoxin in Saccharomyces cerevisiae.

Recent reports showed that whole extract of Podophyllum hexandrum was radioprotective in mice. Podophyllotoxin is one of the major constituents of the whole extract of Podophyllum. In this study we report on the radioprotective action of podophyllotoxin in Saccharomyces cerevisiae yeast. Proliferating yeast cells pretreated with podophyllotoxin (2.5-5.0 microg/mL) for > or =3 hours showed a higher surviving fraction after (60)Co-gamma-irradiation (200-600 Gy) than did the irradiated cells not pretreated with podophyllotoxin. The maximum increase (2.0 times) in surviving fraction was observed in cells treated with 2.5 microg/mL podophyllotoxin, 5 hours before (60)Co-gamma-irradiation (400 Gy). Podophyllotoxin was not mutagenic or recombinogenic at radioprotective doses (2.5 microg/mL). A post-irradiation decrease in revertants and gene convertants was observed in cells treated with podophyllotoxin (2.5 microg/mL podophyllotoxin, -5 hours, 400 Gy). This study indicates that podophyllotoxin is radioprotective in yeast, and its radioprotective effects in higher eukaryotes would be worth investigating.     

Assessment of atmospheric microbial contamination in a mobile dental unit.

INTRODUCTION: Bioaerosols are important considerations in infection control as well as in occupational health. Bioaerosols may carry potentially hazardous microbes, viruses, fungi, allergens, and other toxic substances that may harm the dental operator, patient, and the dental assistant by causing nosocomial infections. OBJECTIVE: To assess the level of atmospheric microbial contamination before, during, and after dental treatment procedures in the dental operatory of a mobile dental unit (MDU). MATERIALS AND METHODS: The study included three treatment sessions on different working days, with an interval of one month. The MDU was fumigated before the start of the study. Brain Heart Infusion Agar with 5% sheep blood was used to collect the gravitometric settling of aerosols produced before, during, and after dental treatment procedures. The agar plates were sent for aerobic and anaerobic culture. RESULTS: The results showed that atmospheric microbial contamination (CFUs/plate) was 4 times higher during working sessions as compared to the levels before the working sessions. At the end of the working day, aerosols decreased by almost 3 times that seen during work. CONCLUSION: The aerosols increased during and after work sessions. This shows the increased risk of transmission of infectious agents to the dentists who work in the MDU. Hence, all necessary preventive measures should be advised and need to be followed strictly.     

Abrogation of DTH response and mitogenic lectin- and alloantigen-induced activation of lymphocytes by calcium inhibitors TMB-8 and BAPTA-AM

In vitro treatment of mouse lymphocytes with an intracellular calcium chelator BAPTA-AM significantly decreased lectin Concanavalin-A (Con-A)-induced and mixed lymphocyte reaction (MLR) mediated, alloantigen-induced lymphocyte activation as indicated by decreased percentage of lymphoblasts among the BAPTA-treated lymphocytes. In vivo treatment of mice with intracellular Ca(2+) antagonist TMB-8 was found to substantially impair delayed type hypersensitivity (DTH; cell mediated immune) response, as indicated by decreased footpad swelling on tuberculin challenge of mice sensitized with BCG, after a single treatment with a low dose of 0.01mg of TMB-8 per mouse. Interestingly, a second injection of a higher dose of TMB-8 (0.1mg per mouse) resulted in very significant (p=0.001) abrogation of DTH as indicated by complete absence of swelling of foot pad after PPD challenge in BCG-primed treated mice. All mice in this group showed fully impaired DTH response. Lymphocytes of allosensitized mice gave a significantly higher (p<0.05) MLR response than the na?ve mice. However, a single treatment of allosensitized mice with 0.1mg TMB-8 resulted into a lower MLR response, comparable in magnitude to that of untreated na?ve mice.     

The newer unconventional indications of permanent pacemakers

In recent years, the indications for permanent pacemakers have expanded. The interest has focussed on hypertrophic cardiomyopathy, dilated cardiomyopathy and a new entity called hypertensive hypertrophy with cavity obliteration (HHCO). Pacemaker therapy is establishing itself for the prevention of atrial fibrillation. Pacing for neurocardiogenic syncope with newer pacing mode has encouraging datas. Pacemaker for long QT syndrome, after cardiac transplant and for haemodynamic improvement in occasional cases of first degree atrio-ventricular block is getting attention. The AHA and ACC guidelines updated in 1998 for implantation of cardiac pacemakers, now include several of these newer indications.     

Incorporating ideas from computer-supported cooperative work

Many information systems have failed when deployed into complex health-care settings. We believe that one cause of these failures is the difficulty in systematically accounting for the collaborative and exception-filled nature of medical work. In this methodological review paper, we highlight research from the field of computer-supported cooperative work (CSCW) that could help biomedical informaticists recognize and design around the kinds of challenges that lead to unanticipated breakdowns and eventual abandonment of their systems. The field of CSCW studies how people collaborate with each other and the role that technology plays in this collaboration for a wide variety of organizational settings. Thus, biomedical informaticists could benefit from the lessons learned by CSCW researchers. In this paper, we provide a focused review of CSCW methods and ideas-we review aspects of the field that could be applied to improve the design and deployment of medical information systems. To make our discussion concrete, we use electronic medical record systems as an example medical information system, and present three specific principles from CSCW: accounting for incentive structures, understanding workflow, and incorporating awareness.     

Renal failure in haemorrhagic shock in dogs: Salutary effects of the calcium entry blocker felodipine

Summary The efficacy of felodipine, a dihydropyridine calcium entry blocker to restore renal function was investigated in Wiggers model of haemorrhagic shock. Mongrel dogs were anaesthetized with sodium pentobarbital and subjected to haemorrhagic shock by allowing the animals to bleed into a reservoir. After maintaining the hypotensive state (mean blood pressure 40–45 mm Hg) for a period of 150 min, the blood was reinfused and the recovery of the various parameters were monitored for an additional 120 min. These studies were conducted in three different groups of dogs: (A) Solvent control, (B) Felodipine 0.01 mol/kg i. v., administered 10 min prior to reinfusion of the blood, and (C) Felodipine 0.01 mol/kg i. v., administered prior to haemorrhage. In all the three groups arterial blood pressure returned to similar basal levels following reinfusion. Felodipine administration prior to haemorrhage or before reinfusion (Group B and C) resulted in a 80–95% recovery in the renal blood flow, 60–65% in the glomerular filtration rate, 15–300% in the urine volume and 80–100% in the urinary sodium and potassium excretions. In the vehicle-treated control group, despite a 45% recovery in the renal blood flow, renal function was not restored following reinfusion.The observations made in these studies suggest that felodipine, an arteriolar dilator which also possesses natriuretic properties, could be clinically useful in the treatment of renal failure in haemorrhagic shock. Prevention of cellular calcium overload during ischaemia and reperfusion by this dihydropyridine derivative, may account for its ability to preserve vascular as well as tubular function. Send offprint requests to B. S. Jandhyala at the above address     

Modeling adverse environmental impacts on the reproductive system

When priority topics are being established for the study of women's health, it is generally agreed that one important area on which to focus research is reproduction. For example, increasing attention has been directed to environmental exposures that disrupt the endocrine system and alter reproduction. These concerns also suggest the need to give greater attention to the use of animal toxicologic testing to draw inferences about human reproductive risks. Successful reproduction requires multiple simultaneous and sequential processes in both the male and female, and the effect of toxicity on reproduction-related processes is time dependent. Currently, however, the risk assessment approach does not allow for the use of multiple processes or for considering the reproductive process response as a function of time. We discuss several issues in modeling exposure effects on reproductive function for risk assessment and present an overview of approaches for reproductive risk assessment. Recommendations are provided for an effective animal study design for determining reproductive risk that addresses optimization of the duration of dosing, observation of the effects of exposure on validated biomarkers, analysis of several biomarkers for complete characterization of the exposure on the underlying biologic processes, the need for longitudinally observed exposure effects, and a procedure for estimating human reproductive risk from the animal findings. An approach to characterizing reproductive toxicity to estimate the increased fertility risks in a dibromochloropropane (DBCP)-exposed human population is illustrated, using several reproductive biomarkers simultaneously from a longitudinal rabbit inhalation study of DBCP and an interspecies extrapolation method.